The present invention relates generally to a turret punch press having a pair of upper and lower turrets rotatably mounted to automatically bring respective punches and dies into alignment for punching a variety of holes in sheet materials and, more particularly, to an apparatus for rotating a set of punches and dies at a single punching station in the upper and lower turrets for punching a wider variety of holes with the same turret.
U.S. Pat. No. 4,658,688, assigned to the assignee of the present application, discloses a punch press having multiple punch tool rotatable turrets wherein at least one of the punch tools on each of upper and lower turrets is indexable to different angular orientations. Rotation of the indexable punch tools is accomplished by a slidably mounted motor for engagement with a timing pulley, which through a timing belt and harmonic gear drive, acts to rotate the punch tools. A break and position sensors are also provided. Synchronization of punch and die orientation is achieved through servos and control.
U.S. Pat. No. 4,569,267 discloses a punch press which uses a punch tool assembly which contains at least two punch pins of different diameters or cross-sections which are interchangeable in the working position by a control element which is slidable about the pin support member, and actuating means. When the punch tool assembly is rotatable about the ram to effect the movement of the punch pins from operative to inoperative positions, then a cooperating movable die is provided in order to ensure that the aligned die bores are cooperatively dimensioned and configured with respect to the punch pins. The punch tool assembly is held on the ram and moves with the ram and the pins, when not being used, are held in an elevated position while the operative pin is rigidly locked into a protruding position.